Hi, i’ve got no problem here with Debian 9 / oF master, with a very old integrated intel graphic card. What linux distro and graphic card are you using?
also the output of those command could be useful:
// check the driver is in use
sudo lspci -vnn | grep VGA -A 12
// check x is using it
glxinfo | grep OpenGL
// check you can get oGL on X
cat /var/log/Xorg.0.log | grep DRI
I was going to start to debug as you were suggesting but I have run the 3DPrimitive example and … It is working. No errors. I do not know why but it looks like sometimes when I start the computer the drivers are not catching up my graphics card, and this happens mostly when I have plugged the cable for the monitor into another computer.
Anyway, thanks